Proceed with Caution: How to Safely Recover a Building from a Power Outage

Author: Patrick Bois Schneider Electric Blog

Extreme weather appears to be all too common of late, with multiple devastating hurricanes and major storms hitting the Caribbean, southeastern U.S. and even Ireland over the last couple of months. It seems a good time then, to remind those responsible for power in commercial and industrial buildings of some precautions they should take in recovering from a power outage, especially one that involves water.

Once a building has been without power for any length of time, it’s tempting to want to turn everything back on once utility power comes back online. But that could leave the building in a compromised position with respect to future power protection requirements.

The main concern is the uninterruptible power supplies (UPSs) that protect various loads within a building. The number and type of UPSs installed will vary widely depending on the building and what it’s used for. Hospitals, for example, will likely have multiple UPSs protecting sensitive medical equipment such as MRI and CT scan machines. A typical office building, on the other hand, may have just a few UPSs protecting critical systems such as emergency lighting and security systems.

Whatever the case may be in your buildings, you need to ensure your UPSs survived the outage in good shape before allowing them to be put back in service.

An overabundance of caution is not a bad thing in this circumstance. As an example, a room flooded, a roof broken, a technical room partially destroyed can be a disaster from an energy and safety stand point.

First cut all power to the room because electricity and water just don’t mix. Then conduct a visual check of the UPSs and batteries. One of the main risks is corrosion and humidity making it unsafe to turn back on. Before making any intervention, you must call a technical expert from the UPS manufacturer who is the only person capable to make an in depth analysis.

Following an outage from a storm requires a clear procedure. Step one is to check the environment. Make sure the roof is intact and that no water, dust or anything else that shouldn’t be there is able to get into the building.

Once that’s done, you can focus on the UPSs. Here you’ve got three areas of concern for each UPS: upstream of the UPS to the wiring cabinet and utility power, the UPS and its batteries, and downstream of the UPS to the loads it is protecting.

First comes the visual check of the electrical components including the wiring cabinet and UPS. If the UPS or any of its components show signs of corrosion, it will be best to replace them, but only a UPS manufacturer expert can check all details.

Next, check the viability of all components. This requires you trip all circuit breakers to make sure there’s no energy flowing to the UPS. Likewise, disconnect all downstream components.

Then, one by one, start closing the circuit breakers and testing each line with a voltage meter to ensure power is flowing. If they all check out OK, now it’s time to ask a UPS manufacturer expert to restart the UPS. When the UPS is running, you can start connecting downstream loads. Again, do so one by one and check with the power meter to ensure power is flowing normally.

Yes, this will take a bit of time, but it’s a small price to pay to ensure the safety of your electrical system – and the occupants of your buildings.

To learn more about commercial and industrial business continuity strategies, click here. For additional information about UPSs, check out these complimentary white papers: “The Different Types of UPS Systems” and  “Guidance on What to Do with an Older UPS”.